Madagascar: 23 million-year-old evolutionary treasure at stake

on their island More than 200 species of mammals that have evolved with their own characteristics over the last million years. However, their isolation and human actions are endangering the survival of these unique mammals on earth with hitherto unimaginable speed.

This is one of the main conclusions of a recent paper published in the journal ‘Nature Communications’, which also measures the impact humans have had over the 2500 years that they have lived on the island, and particularly since the 16th century when the island was colonized. Europeans.

Human pressure killed 30 land mammals living on the island. among them are the iconic giant lemurs or pygmy elephants and hippos. In that short time, humans have destroyed a biodiversity equivalent to three million years of evolution.

More than half of mammals are in danger of extinction

Today, 219 mammal species survive in Madagascar (including 109 lemur species), but more than half (120 to be exact) are threatened with extinction due to habitat destruction and overfishing.. 90% of the species can only be found on the island.

“There are entire lineages of unique mammals found only in Madagascar, which are extinct or on the verge of extinction. Unless urgent action is taken, Madagascar will lose 23 million years of mammalian evolutionary history, meaning that all lineages unique to the face of the Earth will never exist again.”, underlines the paper’s main author, Steve Goodman, a biologist at the Field Museum in Chicago and a scientist at the Vahatra Society in Antananarivo, Madagascar.

And even if we start off from the idea that there may be a “recovery” millions of years from now, if lemurs, tenreks, fossae and other Madagascan mammals go extinct, they will need at least 23 million years to recover after a new long evolutionary period. Goodman concludes that in practice “it would be absolutely impossible to save them”. Rather, what the model used for this study meant is that it would take another 23 million years to reach a similar level of evolutionary complexity.

The finding surprised the researchers, especially the study’s co-author, Luis Valente. “It’s a much longer period of time than would be calculated for other islands like New Zealand or the Caribbean,” says biologist Valente of the Naturalis Center for Biodiversity and the University of Groningen in the Netherlands. “Madagascar was already known as a biodiversity hotspot, but this new research contextualizes how valuable it is,” he emphasizes.

Small populations in closed, vulnerable habitats

Madagascar’s isolation is a double-edged sword. And that is, because of the lack of genetic diversity that can coexist in different ecosystems within a few kilometers, it can accelerate the extinction of the region while allowing it to evolve much faster and uniquely. And this smaller populations that have adapted to unique and reduced habitats are more vulnerable being destroyed and gone, they don’t come back.

Based on the results, the researchers insist that Madagascar is at a crossroads when it comes to biodiversity conservation. “There is still a chance to fix things, but basically, we have about five years. “To really make progress in protecting Madagascar’s forests and the organisms they host,” says Goodman.

But The socio-political situation obscures the prospect of this task being accomplished within a reasonable time.. But while the situation on the island is dire, Goodman insists that “no towels can be thrown”. “We have a duty to promote this cause as much as we can and to make sure the world understands it’s now or never,” he concludes.

Reference work: https://www.nature.com/articles/s41467-022-35215-3

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Contact address of the environment department: crizclimatica@prensaiberica.es